Moe elaborate version. Still a one way valve in the breather hose after the motor, but it goes to a catch can. Fill the can with brass wool like Chore Boy to slow down the oil droplets/mist coming out of the metal tube. One metal tube goes into the can. End of the pipe is closed. Holes drilled into the sides of the pipe in the can. Another tube comes out of the can to a hose. Hose to another metal pipe welded or brazed to the exhaust or header pipe. The metal pipe in the exhaust is installed at an angle pointing in the direction of exhaust flow.
The vacuum created by the pipe angled toward the exhaust flow makes for negative pressure in the motor when the one way valve is open.
End result is that the piston has less work to do on the downstroke Less power wasted. Rings work better. Less leaks. Less oil consumption.